Belize/bəˈliːz/ (listen) (formerly British Honduras) is a constitutional monarchy, and the northernmost Central American nation. Belize has a diverse society, comprising many cultures and languages. Even though Creole and Spanish are spoken among the population, Belize is the only country in Central America where English is the official language. Belize is bordered to the north by Mexico, south and west by Guatemala, and to the east by the Caribbean Sea. Belize’s mainland is about 290 kilometers (180 miles) long and 110 kilometers (68 miles) wide.
The Great Blue Hole is a large underwater sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll 70 kilometres (43 mi) from the mainland and Belize City. The hole is circular in shape, over 300 metres (984 ft) across and 124 metres (407 ft) deep. It was formed during several episodes of Quaternary glaciation when sea levels were much lower - the analysis of stalactites found in Great Blue Hole shows that formation has taken place 153,000, 66,000, 60,000, and 15,000 years ago. As the ocean began to rise again, the caves were flooded.